Delivery of controlled doses of medicaments is desirable to avoid overmedication. Overmedication can especially occur when the medicament is in the form of a creme or liquid. For example, while it is highly desirable to carefully control the dosage of medicaments given to infants or children, it can be difficult to measure the proper dose using traditional measuring devices such as measuring cups. When the medicament is in the form of a crème or ointment, such as for example cremes applied to the face to control skin acne, the medicaments are often stored in tubes or other containers that do not provide delivery of precise doses of the medicament. Application of excess amounts of the crème can result in skin irritation and drying. Also, application of creams using fingers can result in contamination of the medicament.
For some medicaments, such as for example the antiseptic Betadyne™, delivery of a controlled dose in a precise location on the skin is desirable to avoid excessive staining of skin or clothing. For certain vaccines, such as the vaccine for gastroenteritis, a hermetically sealed dispenser that can deliver multiple precise doses of the vaccine can reduce waste of both the vaccine and dispensers.
Several devices have been described previously that permit controlled doses of medicaments to be delivered. These devices can be complicated to manufacture, assemble and fill with the medicament. As a result, these devices can be expensive to manufacture and may not be useful for over the counter (“OTC”) medicaments. Another disadvantage of such devices is that air can enter the device during storage or as the medicament is delivered. Air entering the device during storage or delivery of the medicament can cause degradation of the medicament, reducing the efficacy of the medicament or causing spoilage that may require that the medicament be discarded.
For some medicaments, preservatives are added to prevent degradation or spoilage of the medicament before use due to ingress of air or other contaminants. The preservatives can react with the medicament, however, reducing its efficacy. Also, some users can have undesirable adverse reactions to the preservatives in the medicaments.
One-way spray tips for dispensing medicaments in aerosol form or for delivery to the eye have been described in U.S. Pat. No. 5,320,845 to Dr. Daniel Py issued on Jun. 14, 1994, U.S. Pat. No. 5,613,957 to Dr. Daniel Py issued on Mar. 25, 1997, U.S. Pat. No. 5,746,728 to Dr. Daniel Py issued on May 5, 1998, U.S. Pat. No. 5,855,322 to Dr. Daniel Py issued on Jan. 5, 1999 and U.S. Pat. No. 6,053,433 to Dr. Daniel Py issued on Apr. 25, 2000, each of which is hereby incorporated by reference as part of the present disclosure.
Cosmetics, such as creams or liquid make-ups, can also degrade or spoil with exposure to air. Accordingly, it would be desirable to provide a dispenser that could prevent the ingress of air or other contaminants into the medicament, cosmetic or other substance contained within the dispenser, as well as provide improved control of the amount of the substance dispensed therefrom. It also would be desirable to provide a hermetically sealed dispenser that could be used to deliver controlled amounts of other air-sensitive substances, such as for example glues, while preserving unused portions of the substance for later use.
Accordingly, it is an object of the present invention to overcome one or more of the drawbacks and/or disadvantages of the prior art.